Spatially distributed analysis of soil erosion in a mountain catchment

• Published in: Landslides and Engineered Slopes. Experience, Theory and Practice Vol. 1; pp. 721 - 728
• Main Authors: Cuomo, S., Della Sala, M.
• Format: Book Chapter
• Language: English
• Published: CRC Press 2016
• Edition: 1
• Subjects: Unsaturated Soils; Geomorphological Landforms; Unsaturated Pyroclastic Soils; Overland Flow; Soil Conductivity; Flow Detachment; Debris Flows; Overburden; Slope Instabilities; Soil Cover Thickness; Quaternary Continental Deposits; Mountain Catchment; Hyperconcentrated Flows; Shallow Landslides; Detailed Input Data; Slope Angle Map; Soil Suction; Pyroclastic Soils; Soil Thickness; Splash Detachment; Secondary Surge; Volumetric Concentration; Wetting Front; Erosion Depths; Soil Erosion Models
• ISBN: 1138029882; 9781138029880
• DOI: 10.1201/9781315375007-73

A spatial-distributed soil erosion analysis model was applied to a small-sized mountain catchment of Southern Italy, where shallow deposits of loose, cohesionless unsaturated air-fall volcanic (pyroclastic) soils exist. The physically-based LISEM model was used to analyze a past event, taking into account the potential role of both the soil suction and water content, and the spatial variability of soil thickness. The water discharge and the solid concentration at the outlet of the catchment were computed, as well as the spatial distribution of the eroded soil thickness was discussed for the uppermost areas of the catchment. The results of the paper show that the soil suction and the soil conductivity are key factors for the spatial-temporal evolution of both ground infiltration and runoff in the catchment. This chapter shows that the soil suction and the soil conductivity are key factors for the spatial-temporal evolution of both ground infiltration and runoff in the catchment. It deals with a relevant case study of unsaturated soils, with field evidence available for: principal slope instabilities recorded at the uppermost areas of the catchment; the peak total discharge and solid volume at the outlet of the catchment where huge damage was caused. The physically-based LISEM model was used referring to detailed field data for the Digital Terrain Model, soil cover thickness and soil mechanical properties. The achieved results allowed a satisfactory simulation of the past event in terms of total peak discharge and total volume at the outlet of the catchment, and the back-analysed soil conductivity falls in the range of literature for pyroclastic soils. Some new insights were gained as well for soil erosion along the slopes.